Reddit user carrotslice has taken to creating realistic flags that replace the colours with what they might represent. The first 7 that have been posted look great and the interpretations are really interesting.
Despite being a big fan of the Brazil national team and knowing what the Brazil flag looked like I never know what the colours represented. The circle in the centre represents the night sky over Rio for example. The items u/carrotslice decided to use on the flag above don't match their actual representations but are surely recognisable and would be believable to most. Until I read up on what the green and yellow represented, I would not have questioned that they could represent the rainforest and the Amazon river.